The present invention relates to a hybrid optical/electrical switching for data center networks with an optical switching unit.
Data centers, as the backbone of both conventional (e.g., email, messaging, and banking) and emerging (e.g., cloud) computing services, are facing unprecedented challenges due to the ever-growing scale of applications such as video and large scale data processing. In particular, it has been widely recognized that the conventional tree-like data center network (DCN) suffers poor scalability to both the number of servers and bandwidth demand, as well as several other limitations such as single-point-of-failure, limited sever-to-server capacity, and resource fragmentation.
One approach designs new network interconnection topologies that reorganize servers and switches in certain ways such that improved scalability and bisection bandwidth are achieved. However, the resulting complicated structures of these proposed topologies lead to significantly increased wiring complexity and decreased manageability. Another approach preserves the fundamental interconnection topology and deploys other data transmission technologies, such as high-speed wireless local area network (WLAN) and optical switches. In these approaches, normal workload is still carried by the basic tree-structured network but the peak traffic is offloaded to the extra wireless or optical paths.
FIG. 1 shows an exemplary block diagram of a conventional hybrid electrical/optical switching system with a top of rack (TOR) switch 10. The TOR switch 10 is part of the electrical network, and this network includes an aggregate switch 12 and a core switch 14 that allows one server to communicate with other servers. At the junction between the electrical network and the optical network, one optical transceiver in the TOR switch 10 aggregates the traffic from one or more servers 18. Optical switching is achieved directly through an optical switching matrix 20 with reconfigurable optical paths.
With the system of FIG. 1, servers 18 on one server rack 19 can communicate with other servers 18 on one rack. Due to the dynamic nature of the traffic in data center networks, frequent reconfiguration of the optical switching matrix is expected. However, due to the relatively low switching speed of commercially available optical switching matrix, the optical switching part will suffer from large latency, and may have limited performance in improving the network communication throughput.